1. Field of the Invention
This invention relates to information systems. More particularly, the invention relates to systems and methods for controlling access rights to digital contents in a Distributed Information System (DIS), e.g., the Internet.
2. Description of Prior Art
Owners of digital content stored and available to the public in an information system would like to ensure that payment has been received in some form and use restrictions observed prior to granting access rights to use the contents. Such access rights can be limited to a particular user for a limited period of time. Information handlers which enforce an owner's content restrictions, for example, restricting the user's right to save content to a storage device are presently available to owners. However, in order to make use of such content restrictions practical in a widely-distributed environment, such as the Internet, there must be a mechanism by which the appropriate information-handler can be readily identified and supplied with contents in a secure manner. A trusted information handler is a mechanism that permits limited access to digital content as specified by the owner of that content. Such trusted information handler should be easily replaced enabling new forms of content to be accessed in a secure manner. Also, such mechanism should permit the easy addition and replacement of such handlers.
Prior art related to limiting access rights to digital content in an information system includes the following:
U.S. Pat. No. 5,436,972 discloses a method for preventing inadvertent betrayal by a trustee of escrowed digital secrets. After unique identification data describing a user has been entered into a computer system, the user is asked to select a password to protect the system. All personal identifying data, together with the password, is encrypted with a trustee's public key and stored, for example, in the user's computer system as an escrow security record. The password is then used to encrypt all data on the user's disk. If at some point in time, the user forgets the password, the user contacts the trustee's, for example, the vendor or the manufacturer. The trustee utilizes documentary evidence presented by the alleged legitimate user and determines whether such evidence matches with the previously encrypted escrowed information stored in the escrow records created by the user. If the records agree, then the trustee has confidence that the true owner is making request and that revealing the secret password will not betray the owner's interest.
U.S. Pat. No. 5,557,518 issued Sept. 17, 1996, discloses a system to open electronic commerce using trusted agents. A customer-trusted agent securely communicates with a first money module. A merchant-trusted agent securely communicates with a second money module. Both trusted agents are capable of establishing a first cryptographically-secure session. Both money modules are capable of establishing a second cryptographically-secure session. The merchant-trusted agent transfers electronic merchandise to the customer-trusted agent, and the first money module transfers electronic money to the second money module. The money module informs the trusted agents of the successful completion of payment and the customer may use the purchased electronic merchandise.
U.S. Pat. No. 5,557,765 discloses a system and method for data recovery. An encrypting user encrypts a method using a secret storage key (KS) and attaches a Data Recovery Field (DRF), including an Access Rule Index (ARI) and the KS to the encrypted message. The DRF and the encrypted message are stored in a storage device. To recover the storage key (KS) a decrypting user extracts and sends the DRF to a Data Recover Center (DRC) and issues a challenge based on Access Rules (ARs) originally defined by the encrypting user. If the encrypting user meets the challenge, the DRC sends the KS in a message to the encrypting user. Generally, KS need not be an encryption key but could represent any piece of confidential information that can fit inside the DRF. In all cases, the DRC limits access to decrypting users who can meet the challenge to find in either the ARs defined by the encrypting user or the ARs defined for override access.
U.S. Pat. No. 5,590,199 issued Dec. 31, 1996, filed Oct. 12, 1993, discloses a system for authenticating and authorizing a user to access services on a heterogenous computer network. The system includes at least one workstation and one authorization server connected to each other through a network. A user couples a personally protectable coprocessor (smart card) to the workstation by means of a bidirectional communications channel. The coprocessor is adapted to receive signals including first encrypted authentication information and decrypt the first encrypted authentication information using a preselected first key. The coprocessor is further adapted to assemble and encrypt second authentication information using a preselected second key and to transmit the encrypted second encrypted authentication information to the workstation. The workstation then communicates the information on to the network whereby the user is authenticated to access the network computer or service.
U.S. Pat. No. 4,827,508; U.S. Pat. 4,977,594 issued Dec. 11, 1990, a division of the '508 patent, and U.S. Pat. No. 5,050,213 issued Sept. 17, 1991, a continuation of the '594 patent, disclose a database access system and method at a user site which permits authorized users to access and use the database and prevent unauthorized database use and copying. A facility is disclosed for measuring usage of the on-site database for purposes of billing the user according to the amount the database has been used. Periodically, the measured usage information is conveyed to the database owner while preventing the user from tampering with the measured usage information.
None of the prior art discloses a system and method for using a trusted information handler and a digital container techniques in an information network which assures that an owner's digital content is not accessed without the owner's permission and use restrictions observed, thereby enabling valuable digital content to be transferred and/or sold electronically with the assurance that the owner's rights are fully protected.